This proposal relates to the development of bioluminescent reagents composed of firefly or bacterial luciferase convalently linked to specific binding proteins (SBP) such as monoclonal antibodies, polyclonal antibodies, lectins, and protein A. These conjugates will be evaluated as reagents in luminescent immune assays (LIA) and as immunoluminescent stains (ILS). Proposed applications include the identification and assay of macromelecular antigens, small molecules such as drugs or hormones, cell labeling for flow cytometry/cell sorting, and the localization and visualization of antigens separated by electrophoresis. (2)